It is there... check your version and install path
arcgis.__version__
'1.8.0'
from arcgis.learn import EntityRecognizer
dir(arcgis.learn.EntityRecognizer)
['__class__'... snip...
'_arcgis_init_callback', '_check_backbone_support', '_check_requisites', '_check_tf',
'_create_emd', '_create_emd_template', '_create_html', '_create_tfonnx_emd_template',
'_extract_entities_text', '_find_lr', '_get_emd_params', '_get_post_processed_model',
'_get_tfonnx_emd_params', '_model_metrics', '_post_process_address_df',
'_post_process_non_address_df', '_publish_dlpk', '_save', '_save_as_tfonnx',
'_save_model_characteristics', '_save_tflite', '_show_lr_plot', '_write_emd',
'extract_entities', 'fit', 'from_model', 'load', 'lr_find', 'save', 'show_results',
'unfreeze'
]